/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.skatiger.jrove.servlet;

import java.util.Enumeration;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.skatiger.jrove.servlet.enumeration.EmptyEnumeration;

public final class SessionMap extends AbstractAttributeMap<Object> {
    private final HttpServletRequest _httpRequest;

    SessionMap(final HttpServletRequest httpRequest) {
        _httpRequest = httpRequest;
    }

    /**
     * This will clear the session without invalidation. If no session has been
     * created, it will simply return.
     */
    @Override
    public void clear() {
        final HttpSession session = getSession();
        if (session == null) {
            return;
        }
        for (final Enumeration<?> attributeNames = session.getAttributeNames(); attributeNames.hasMoreElements();) {
            final String attributeName = (String) attributeNames.nextElement();
            session.removeAttribute(attributeName);
        }
    }

    @Override
    protected Object getAttribute(final String key) {
        final HttpSession httpSession = getSession();
        return (httpSession == null) ? null : httpSession.getAttribute(key);
    }

    @Override
    @SuppressWarnings("unchecked")
    protected Enumeration<String> getAttributeNames() {
        final HttpSession httpSession = getSession();
        return (httpSession == null) ? EmptyEnumeration.instance() : httpSession.getAttributeNames();
    }

    private HttpSession getSession() {
        return _httpRequest.getSession(false);
    }

    @Override
    public void putAll(final Map<? extends String, ? extends Object> t) {
        throw new UnsupportedOperationException();
    }

    @Override
    protected void removeAttribute(final String key) {
        final HttpSession httpSession = getSession();
        if (httpSession != null) {
            httpSession.removeAttribute(key);
        }
    }

    @Override
    protected void setAttribute(final String key, final Object value) {
        _httpRequest.getSession(true).setAttribute(key, value);
    }
}